Hi everyone. I am working on deferred shading because I want to add this to my own engine. Currently geometry phase and directional lights from lighting phase are working fine on both versions of directx 9 and 11.
I stucked on points lights. Here is a shader's code for point light:

I would suggest outputting your position to make sure that you're reconstructing the correct value. You can also try outputting your normals to verify that they're correct. You can also debug your shader in PIX or the VS 2012 graphics debugger, so that you can step through and see where you're going wrong. And if you haven't enabled debug output when creating your device, then you should do so to ensure that you catch any errors.